JPH07247401A - Primer material for photosensitive resin - Google Patents

Abstract

PURPOSE:To obtain the material useful in excimer laser lithography by forming a layer containing a polyglycidyl acrylate and a light absorbent for low wave length between the base and the photosensitive resin layer to prevent the irregu lar reflection of irradiation light from the base and development of stationary waves. CONSTITUTION:This primer material contains a polyglycidyl acrylate (preferably having 5,000 to 300,000 weight-average molecular weight) and a light absorbent having an absorption in less than 400nm wavelength, preferably an azo compound of formula I {R1-R5 each is H, a halogen, a (substituted) alkyl, alkoxy, OH, nitro, -COOR7 [R<7> is H or a (substituted) alkyl]; R6 is formula II (R8 is an alkyl), a (substituted) naphthyl, formula III [R9, R10 are H, a (substituted) alkyl, an aryl]}.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection base material for a photosensitive resin used for lithography with light having a wavelength of 400 nm or less (ultraviolet rays including i-rays and far ultraviolet rays including excimer lasers).

[0002]

2. Description of the Related Art Recently, a chemically amplified resist has attracted attention as a photosensitive resin for 64M and 256M DRAMs (designed to have a size of half micron or less). The chemically amplified resist utilizes the difference in solubility between the exposed area and the unexposed area in an alkali developing solution, and utilizes the reaction of the acid generated from the acid generator by the irradiation of Kr F excimer laser (248 nm) as a catalyst. is doing. The substrate used to form the semiconductor integrated circuit element has various steps and irregularities on its surface. When a photosensitive resin solution is applied to such a substrate, the film thickness becomes thicker in the concave portion and thinner in the convex portion, resulting in a coating film. The surface of the becomes wavy. This causes variations in the exposure characteristics of the resist and reduces the accuracy of pattern dimensions. In particular,
If the substrate has a high reflectance such as aluminum,
Irregular reflection of the irradiation light may be significant and the resist pattern may not be formed. In a conventional positive resist containing an alkali-soluble resin and a quinonediazide-based photosensitizer, polymethyl methacrylate or a dye containing a dye between the substrate and the resist film for the purpose of eliminating irregularities on the substrate surface and suppressing reflection from the substrate. A method for forming a film of polymethylisopropenyl ketone has been disclosed (for example, Japanese Patent Laid-Open No. 58-51517). As described above, in the conventional resist, no problem occurs even if polymethylmethacrylate or the like is used as the base material. However, for example, when the above chemically amplified resist is used, the conventional base material absorbs the acid generated from the acid generator in the chemically amplified resist, and inhibits the reaction using the acid as a catalyst. There was a point. Further, in the lithography using a light having a single wavelength and a uniform phase such as a Kr F excimer laser, another problem that a standing wave is easily generated on a flat substrate having no unevenness occurs. Therefore, it is necessary to solve the above problems in order to form a fine pattern with high resolution.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and provides a base material for a photosensitive resin, which suppresses reflection from a substrate and prevents standing waves even in lithography such as deep ultraviolet rays. To do.

[0004]

The present invention is a base material for a photosensitive resin, which comprises polyglycidyl acrylates and a light absorber having absorption at a wavelength of 400 nm or less. The above-mentioned light absorber is preferably, for example, one represented by the general formula (I)

[0005]

[Chemical 4]

[In the formula, R _{1 to} R ₅ each independently represent a hydrogen atom, a halogen atom, an optionally substituted alkyl or alkoxy group, a hydroxyl group, a nitro group or —COOR ₇ , and R ₇ is hydrogen. Represents an atom or an optionally substituted alkyl group. R ₆ is the following formula

[0007]

[Chemical 5]

(In the formula, R ₈ represents an alkyl group), an optionally substituted naphthyl group or the following formula

[0009]

[Chemical 6]

(In the formula, R ₉ and R ₁₀ each independently represent a hydrogen atom or an optionally substituted alkyl or aryl group). ] The azo compound etc. which are shown by these are mentioned. In the general formula (I), R _{1 to} R
_The optionally substituted alkyl group represented by ₅ may be branched, and preferably has 1 to 5 carbon atoms, more preferably a methyl or ethyl group. The alkoxy group which may be substituted is preferably a methoxy group or an ethoxy group. Examples of the substituent of the alkyl and alkoxy groups include a halogen atom and a hydroxyl group. The optionally substituted alkyl group represented by R ₇ may be branched, and preferably has 1 to 5 carbon atoms, more preferably a methyl or ethyl group. Preferred R _{1 to} R ₅ are hydrogen atoms,
Halogen atom, an alkyl group of 1 to 5 carbon atoms, a nitro group or a -COOR _7. The alkyl group represented by R ₈ is preferably one having 1 to 5 carbon atoms, and more preferably a methyl or ethyl group. As the substituent of the naphthyl group represented by R ₆ , a hydroxyl group,
An alkoxy group etc. are mentioned. Further, the substituent of the alkyl or aryl group represented by R ₉ and R ₁₀ includes a hydroxyl group, —OR ₁₅ , —CN, —NO ₂ , and —OCOR.
₁₆ , --SO ₂ NHR _{16 and the} like. Here, examples of R ₁₅ include an alkyl group and the like, preferably 1 to 5 carbon atoms.
And more preferably a methyl group or an ethyl group. Examples of R ₁₆ include an alkyl group having 1 to 5 carbon atoms or an aryl group. Examples of the azo compound represented by the general formula (I) include the following compounds.

[0011]

[Chemical 7]

The azo compounds represented by the general formula (I) are "dye chemistries" (Abeda and Imada, Shikisosha, 1989).
It can be easily produced according to the method described in, etc., and can be obtained, for example, by diazotizing a substituted aniline and then performing a coupling reaction with a predetermined heterocyclic, aniline or naphthalene intermediate. .

The polyglycidyl acrylates include
Examples thereof include a homopolymer of glycidyl methacrylate or a copolymer of glycidyl methacrylate and an alkyl methacrylate or acrylonitrile.
Any of these polymers can be easily produced by an ordinary radical polymerization reaction.

The weight average molecular weight of the polyglycidyl acrylates is usually 2000 to 500000, preferably 5000 to 300000. The molar ratio of glycidyl methacrylate to another monomer (for example, methacrylic acid alkyl ester or acrylonitrile) to be copolymerized is determined in an appropriate range in consideration of coating property and curing time, but is usually 1: 9.
˜9: 1, preferably 4: 6 to 8: 2.

In the base material of the present invention, the amount of the above light absorber is usually 0.1 to 30 parts by weight, preferably 0.2 to 20 parts by weight, based on 100 parts by weight of polyglycidyl acrylates. If necessary, a curing agent may be used in combination with the base material of the present invention. As a preferable curing agent used in combination, for example, a heat curing agent can be mentioned. Examples of the thermosetting agent include alkylamines such as hexamethylenediamine, aromatic amines such as aminophenol, phenols such as bisphenol S, and dimers of the above phenols. The amount of the curing agent is usually 0.0001 to 0.1 part by weight, preferably 0.0005 to 0.05 part by weight, based on 100 parts by weight of polyglycidyl acrylates. If necessary, for example, an electron-donating organic substance or a sensitizer such as a photoacid generator may be used in combination with the above-mentioned base material. Preferable electron-donating organic substances to be used in combination include, for example, polycyclic aromatic compounds such as anthracenes, pyrenes and carbazoles. The photoacid generator is preferably, for example, halogenated alkyls such as tris (2,3-dibromopropyl) isocyanurate, trifluoromethanesulfonic acid esters, arylsulfonylacetophenones, disulfone compounds such as diphenyldisulfone, and trifluoromethanesulfonate. Examples thereof include onium salts such as phenylsulfonium salt and diphenyliodonium salt. The amount of the sensitizer is usually 0.01 to 10 parts by weight, preferably 0.1 to 100 parts by weight of polyglycidyl acrylates for an electron-donating organic substance.
1 to 5 parts by weight, and in the case of the photoacid generator, it is usually 0.001 to 5 parts by weight, preferably 0.01 to 2 parts by weight, based on 100 parts by weight of polyglycidyl acrylates.

The solvent that can be used when the base material of the present invention is used for a photosensitive resin is preferably one which has an appropriate drying rate and gives a uniform and smooth coating film. Examples of such a solvent include cellosolve esters such as ethyl cellosolve acetate and methyl cellosolve acetate, propylene glycol esters such as propylene glycol monomethyl ether acetate, and ketones such as methyl isobutyl ketone and heptanone. The amount of the solvent is not particularly limited as long as it is possible to apply a film that is homogeneous on the wafer and has no pinholes and uneven coating, but for example, when propylene glycol monomethyl ether acetate is used, the resist composition is preferably used. 50 to 95% by weight based on the total weight of.

The photosensitive resin is preferably a chemically amplified positive or negative type resist, and the former is, for example, t-butoxycarbonyl (t-BOC) having a hydroxyl group of bisphenol A.
) Is a composition comprising a dissolution inhibitor such as a compound protected by a group, an alcal-soluble resin and an acid generator, the latter being a crosslinking agent such as hexamethoxymethylolated melamine,
A composition comprising an alcal-soluble resin and an acid generator.

[0018]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, “part” means “part by weight”.

Example 1 100 parts of polyglycidyl methacrylate (polystyrene-converted weight average molecular weight 212000), the following formula

[0020]

[Chemical 8]

13 parts of the azo compound represented by and 900 parts of propylene glycol monomethyl ether acetate (manufactured by Kuraray Co., Ltd.) were mixed and dissolved, and filtered through a Teflon filter having a pore size of 0.1 μm to prepare a base material solution.

Example 2 A base material solution was prepared in the same manner as described above except that 5 parts of 9-anthracenemethanol (manufactured by Aldrich) was added to the composition of Example 1. Example 3 A base material solution was prepared in the same manner as above except that 2 parts of diphenyldisulfone was added to the composition of Example 1.

Reference Example 1 Copolymer of styrene and p-hydroxystyrene [Maruzen Petrochemical linker CST-70, molecular weight 2300] 10 parts, hydrogenated polyvinylphenol [Maruzen Petrochemical linker PHM-
C, molecular weight 5400] 90 parts, hexamethoxymethylolated melamine (crosslinking agent) 15 parts and tris (2,3-dibromopropyl) isocyanurate (photo acid generator) 7 parts were mixed with 370 parts propylene glycol monomethyl ether acetate. By dissolving, a photosensitive resin (chemically amplified negative resist) solution was prepared.

Example 4 A wafer having a stepped 0.5 μm thick SiO ₂ layer on a silicon plate was coated with aluminum to a thickness of 500 to 700 nm on a silicon substrate. After coating, baking was performed on a contact type hot plate at 230 ° C. for 5 minutes to obtain a base film having a thickness of 1.0 μm. The photosensitive resin solution obtained in Reference Example 1 was spin coated thereon to a thickness of 0.7 μm, prebaked on a contact type hot plate at 100 ° C. for 1 minute, and then subjected to a KrF excimer laser stepper (NSR-1755 EX8A NA manufactured by Nikon Corporation). = 0.45) and exposed with a laser beam having a wavelength of 248 nm. After the exposure, the film was baked on a contact type hot plate at 100 ° C. for 1 minute, and then paddle developed with a 2% aqueous solution of tetramethylammonium hydroxide for 1 minute. The pattern obtained is 0.35 at an exposure dose of 70 mJ / cm ² .
The line and space of μm was resolved 1: 1 (the flat part above the step). In addition, the resist pattern that intersects with the stepped portion on the surface of the base material on the silicon plate is measured with a line width measuring instrument [manufactured by Hitachi, Ltd.] above and below the stepped portion, and the result is equivalent to a peak and a valley. The line size difference in the part was small, and no line break was observed.

Example 5 A substrate similar to that in Example 1 was spin-coated with the undercoating material solution obtained in Example 2 and baked in a convection oven at 150 ° C. for 30 minutes to obtain a 1.0 μm-thick undercoating film. It was On top of this,
The photosensitive resin solution obtained in Reference Example 1 was spin-coated to a thickness of 0.7 μm, prebaked on a contact hot plate at 100 ° C. for 1 minute, and exposed and developed in the same manner as in Example 1 to obtain a pattern. The pattern obtained is 0.35μ at an exposure dose of 60 mJ / cm ² .
The line and space of m was resolved 1: 1 (the flat part above the step). As for the resist pattern that crosses the step on the surface of the underlying material on the silicon plate, the line width measuring instrument measured the size above and below the step, and as a result, the difference in line size between the peak and the valley was small. No line break was observed.

Example 6 A substrate similar to that in Example 1 was spin-coated with the undercoating material solution obtained in Example 3 and then baked in a convection oven at 150 ° C. for 30 minutes to obtain a 1.0 μm-thick undercoating film. It was On top of this,
The photosensitive resin solution obtained in Reference Example 1 was spin-coated to a thickness of 0.7 μm, prebaked on a contact hot plate at 100 ° C. for 1 minute, and exposed and developed in the same manner as in Example 1 to obtain a pattern. The pattern obtained is 0.35μ at an exposure dose of 45 mJ / cm ² .
The line and space of m was resolved 1: 1 (the flat part above the step). As for the resist pattern that crosses the step on the surface of the underlying material on the silicon plate, the line width measuring instrument measured the size above and below the step, and as a result, the difference in line size between the peak and the valley was small. No line break was observed.

Comparative Example 1 The same substrate as in Example 1 was spin-coated with the photosensitive resin solution obtained in Reference Example 1 to a thickness of 0.7 μm, and then prebaked on a contact type hot plate at 100 ° C. for 1 minute. Exposure and development were performed in the same manner as in 1 to obtain a pattern. A line-and-space pattern of 0.35 μm was obtained at an exposure dose of 70 mJ / cm ² (flat portion above the step). However, as a result of measuring the dimension of the resist pattern that intersects the step on the silicon plate at the top and bottom of the step with a line width measuring device, the line dimension difference at the part corresponding to the peak and the valley is large, and A break in the line was recognized.

[0028]

EFFECTS OF THE INVENTION When a film is formed on a substrate by using the base material for a photosensitive resin of the present invention, and then a photosensitive resin (particularly a chemically amplified resist) film is formed on the formed film, a high resolution is obtained. Moreover, a fine pattern can be accurately formed.

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[Procedure amendment]

[Submission date] May 27, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Example 5 A substrate similar to that of Example 4 was spin-coated with the undercoating material solution obtained in Example 2 and baked in a convection oven at 150 ° C. for 30 minutes to obtain a 1.0 μm-thick undercoating film. It was On top of this,
The photosensitive resin solution obtained in Reference Example 1 was spin-coated to a thickness of 0.7 μm, prebaked on a contact hot plate at 100 ° C. for 1 minute, and exposed and developed in the same manner as in Example 1 to obtain a pattern. The pattern obtained is 0.35μ at an exposure dose of 60 mJ / cm ² .
The line and space of m was resolved 1: 1 (the flat part above the step). As for the resist pattern that crosses the step on the surface of the underlying material on the silicon plate, the line width measuring instrument measured the size above and below the step, and as a result, the difference in line size between the peak and the valley was small. No line break was observed.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

Example 6 A substrate similar to that in Example 4 was spin-coated with the undercoating material solution obtained in Example 3 and then baked in a convection oven at 150 ° C. for 30 minutes to obtain a 1.0 μm-thick undercoating film. It was On top of this,
The photosensitive resin solution obtained in Reference Example 1 was spin-coated to a thickness of 0.7 μm, prebaked on a contact hot plate at 100 ° C. for 1 minute, and exposed and developed in the same manner as in Example 1 to obtain a pattern. The pattern obtained is 0.35μ at an exposure dose of 45 mJ / cm ² .
The line and space of m was resolved 1: 1 (the flat part above the step). As for the resist pattern that crosses the step on the surface of the underlying material on the silicon plate, the line width measuring instrument measured the size above and below the step, and as a result, the difference in line size between the peak and the valley was small. No line break was observed.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

Comparative Example 1 The same substrate as in Example 4 was spin-coated with the photosensitive resin solution obtained in Reference Example 1 to a thickness of 0.7 μm, and then prebaked on a contact hot plate at 100 ° C. for 1 minute. Exposure and development were performed in the same manner as in 1 to obtain a pattern. A line-and-space pattern of 0.35 μm was obtained at an exposure dose of 70 mJ / cm ² (flat portion above the step). However, as a result of measuring the dimension of the resist pattern that intersects the step on the silicon plate at the top and bottom of the step with a line width measuring device, the line dimension difference at the part corresponding to the peak and the valley is large, and A break in the line was recognized.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03F 7/027 502 7/11 503 // C07D 231/44 (72) Inventor Hiromi Oka Osaka Osaka Sumino Chemical Industry Co., Ltd., 3-98 Kasuga, Konohana-ku, Yokohama (72) Inventor Yuko Nakano 3-98, Kasuga-de, Konohana-ku, Osaka City, Osaka

Claims (6)

[Claims] 1. Polyglycidyl acrylates and 400 nm
A base material for a photosensitive resin, which comprises a light absorber having absorption at the following wavelengths. 2. A light absorber having the general formula (I): [In the formula, R _{1 to} R ₅ are each independently a hydrogen atom, a halogen atom, an optionally substituted alkyl or alkoxy group, a hydroxyl group, a nitro group or —COOR ₇
And R ₇ represents a hydrogen atom or an optionally substituted alkyl group. R ₆ is the following formula (In the formula, R ₈ represents an alkyl group),
An optionally substituted naphthyl group or the following formula: (In the formula, R ₉ and R ₁₀ each independently represent a hydrogen atom or an optionally substituted alkyl or aryl group.) ] The base material of Claim 1 which is an azo compound shown by these. 3. The base material according to claim 1, wherein the polyglycidyl acrylate is a copolymer of glycidyl methacrylate and an alkyl methacrylic acid ester. 4. The base material according to claim 1, wherein the photosensitive resin contains at least an alkali-soluble resin as a main component. 5. The method according to claim 1, further comprising an electron-donating organic substance.
The base material according to any one of to 4. 6. The method according to claim 1, further comprising a photo-acid generator.
The base material according to any one of 1.